1. Field of the Invention
The present invention relates to a virtual local area network(VLAN) data switching method using ARP packets, and more particularly, to a VLAN data switching method using an address resolution protocol(ARP) packet in a virtual local area network(VLAN) constructed with one IP subnet.
2. Background of the Related Art
Generally, local area network(LAN) is an information communication network enabling data communications between a plurality of computers. There are a variety of structures for LAN in accordance with their usages. Lately, in order to prevent the degradation of LAN performance due to broadcast traffic, a virtual local area network(VLAN) system divided into a plurality of VLANs operating in a manner that the same as a LAN has been developed.
In a VLAN a plurality if virtual LANs are separated in one switch so that a broadcast traffic occurring in one VLAN causes no influence on the traffic of other VLANs by separating their broadcasting domains.
Communication between VLANs is achieved by routing methods. First, one internet protocol(IP) subnet is allocated to one VLAN so that the communication between different VLANs is converted into a communication between different IP subnets. Second, a plurality of VLANs are allocated to one IP subnet.
In an environment where a plurality of VLANs are set up in one IP subnet, a packet communication between hosts connected to a switch is divided into an intra-VLAN traffic and an inter-VLAN traffic. In this case, intra-VLAN traffic is a traffic occurring when a packet is transmitted from one host to another host belonging to the same VLAN, while inter-VLAN is a traffic occurring when a packet is transmitted to another host belonging to another VLAN.
The communication between hosts belonging to one IP subnet recognizes a media access control(MAC) address of the corresponding host by generating an address resolution protocol(ARP) request message directly to the host for communication therewith.
FIG. 1 illustrates a diagram for a general VLAN data switching system, in which broadcasting domains are separated by separating a plurality of VLANs(VLAN1 and VLAN2) in one router so that a broadcast traffic occurring in one VLAN has no effect on the traffic of other VLANs.
A method of switching data between different VLANs is explained by referring to the above drawing.
Referring to FIG. 1, in order to transmit data from a source host P1 belonging to VLAN1 to a destination host P2 belonging to VLAN2, the source host P1 acquires an MAC address of a router R and then transmits a frame to the router R. The router R detects and analyzes the IP address information of the transmitted frame, and then generates a MAC address of the destination host P2. In this case, the MAC address of the source is changed into the MAC address of the router R, and the MAC address of the destination is changed into the MAC address of the destination host P2 corresponding to the destination IP address for transmission to the destination host P2.
Unfortunately, the VLAN data switching method according to the related art carries out the routing procedure via inter-VLAN traffic in a different VLAN environment, thereby a network bottleneck is concentrated on and causes a burden to a control processing unit(CPU) performing the routing operations.
Moreover, the VLAN data switching method according to the related art causes undesirable delays in data transfer time as well as increasing loads on the CPU in handling traffic between different VLANs.
Although, conventional hardware such as a forwarding engine of a high-speed router may be a solution for the above problems. Such additional hardware increases the overall cost of handling traffic.